Method of making a homogeneous mechanical juncture.



A. B. HERRICK.

METHOD OF MAKING A HOMOGENEOUS MECHANICAL JUNCTURE.

APPLICATIO" FILED NOV.29, 1912.

1,142,428. Patented June 8', 1915.

2 SHEETS-SHEET 1- WNW/E665 s: 1 ENT E5 7770 EMA-2V6 A. B. HERRICK.

METHOD OF MAKING A HOMOGENEOUS MECHANICAL JUNCTURE.

APPLICATION FILED NOV. 29, 1912.

1,142,428. PatentedJune s, 1915.

2 SHEETS-SHEET 2.

4 fig 5- HTT'OIE'NE V6 I UNITED STATES PATENT oEEioE.

ALBERT :e. HERRICK, or NEW YORK, N. Y., ASSIGNOR 110 THE ELECTRIC RAILWAY IMrEovEpi NT COMPANY, or CLEVELAND, OHIO, A CORPORATION or OHIO.

METHOD OF MAKING A HOMOGENEOUS MECHANICAL JUNCTURE.

Specification of Letters Patent.

Patented June 8, 191 5.

Application filed November 29, 1912. Serial No. 733,975.

To all whom it may concern Be it known that I, ALBERT B. HERnioK, a citizen. of the United States, and a resident of New York, county of New York, and State of New York, have invented a new and useful Improvement in Methods of Making a Homogeneous Mechanical Juncture, of which the following is a specification, the principle of the invention being herein explained and the best mode in which I have contemplated applying that principle, so as to distinguish it from other inventions.

The present process may be regarded as an improvement in the method of making homogeneous mechanical j unctures described in U. S. Letters Patent No. 1,012,077, issued tome December 19,1911, such process having as its object the ,Welding together of metal bodies having unlikecharacteristics as to fusibility, such for example as copper bonds to steel rails in .the operation of bonding rails, as is necessary in electrical railways in order to adapt said rails for use as a conductor for the return circuit. The present improved process has more particular regard to a method of and apparatus for utilizing a direct current of relatively high voltage (500 or 600 volts), which is ordinarily used in the operation of electric railways, in developing the external source of heat which is utilized in my aforesaid patented process. In such patented process, a solid electrode of carbon or equivalent material is designed to be pressed against the bond terminal or equivalent article of relatively lower fusibility and greater heat conductivity, and a heating electric current then passed through said electrode until a high temperature is produced therein, the contacting face of the larger body (having the higher fusibility and'loiver heat conductivity) being heated by conduction through the smaller body, Whereby the smaller body and the contacting face of the larger body are brought to a welding temperature practically simultaneously. A current of low voltage and large amperage is requiredto heat an electrode of the necessary size and area for use in such process and a current such as described above as be ing ordinarily available has accordingly to be converted and stepped down in order to render it available for use in the bonding operation. Theuse of the direct current at relatively high voltage has hitherto been found impracticable Where a Weld or union possessing good electrical conductivity is the result desired; for owing to the arcing efiect and the very high temperature incidentally produced, such current instead of simply fusing the contacting faces of the bodies to be united will more or less vaporize and dissipate the materials of said bodies. and particularly a body of fusible material, such as a bond which is usually composed of copper, and leave the products of such areing in the juncture produced.

The use of direct current at high voltage produces an arc volatilizing and boiling the conductors in its path. This arcing path is so restricted that no areas of any considerable extent can be heated thereby; and. furthermore, after the current once establishes an arcing path, the vapors and moltenma terial offer much less electrical resistance than does the surrounding medium, thus additionally restricting the heating effect to be derived from a current ofthis kind. and rendering the use of a continuous high-tension current by any method at present in commercial use unsuitable for the heating of a surface, as is necessary in the application in hand. Again, in order to keep the volume of current flowing across an are within controllable limits. the arc must have a certain minimum length, and such an arc is easilydeflected by surrounding influences from the point or points where the application of its heating effect is desired. Moreover. the use of a high-tension. arcing electrode not only .volatilizes the material of the electrode but 'also the metals being joined, producing oxides or other deposits which become incorporated in the Weld and render a homo geneous juncture of such metals, e en in the relatively restricted areas that are joined together, a practical impossibility.

It has been found that when a current of high voltage has been applied to a high resistance contact, that the electrodes in contact must first be heated to the point of vaporization to form a molten carrier for the arc; also that there is a time element necessary to be allowed, for a point, or restricted area of high temperature, to effect the rise of temperature of the surrounding media; also that a short application of high voltage and current conditions to a contact point will producesubstantially the same resulting heating effect as a lower energy value continuously applied with the additional advantage that the interrupted current has "not time to raise the volatilizable material in the electrode to a condition suitable for the production of an arcing path. Hence, as

'the desired temperature of the welding electrode is way below the volatilizing temperature, I utilize an electrode made up of a,

plurality. of contact surfaces, or arcing points to which the high voltage current 1s successively, momentarily supphed, the effect being that this momentary application at frequent intervals causes the energy to spread to adjacent surfaces, forming a high temperature area which can be utilized in welding processes'of the kind in hand, without destruction of the physical characteristics of the metals welded. As the application of energy is only for a short interval this current can be used at a number of adjacent heating points and so commutated as to form a cycle of intermittent applications of high temperature impulses, all acting on electrodes, or preferably, an induction de-z 'case where the process is.one of bonding,

and can be controlled in its intensity by a rheostat or, utilizing the intermittent character of the current, I can make its volume controllable by the employment of an induction device, either one induction device common to all the clrcuits to the various vice included on'each electrode circuit. In this way regulation 'of the ultimate tempera ture to befbbtained can be effected by the speed given the contact-arm distributing this current to the various electrodes, keeping in mind that the approximately efl'ec-,

tive voltage applied to any one electrode is determined by the ratio of the time of, con- I tact to the total time elapsed between contacts, as the source of e'lectromotive-force is to the E. M. F. applied to each electrode.

' With the object in view of utilizing a current of the character described, in such an operation as bonding and elsewhere where it is desired to secure a unction having good d1stinguished' electrical conductivity, as from an ordinary mechanical )Olnt. the

present improved steps and means have been devised, all as will be hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail certain steps and mechanism embodying the invention,

' in which the principle of the invention may be used.

In said annexed drawings, Figure 1 is a perspective view, in the nature of a diagram, of a simple form of apparatus adapted for the carrying out of my improved process; Figs. 2, 3 and 4 illustrate in side elevation, plan view and cross-section, re spectively, an electrode which forms a part of said apparatus; Fig. -5 is a perspective view and Fig. 6 a sectionof a modified construction of electrode; while Figs. 7 and 8 respectively illustrate diagrammatically, two

more elaborate apparatuses suitable for the carrying on of my improved process, but utilizing an electrode of the same construction as those shown in the preceding figures. In carrying out the present process. I make use of an electrode consisting of a plurality of insulated elements, as for eX- amplecarbonrods, the inner ends of which are approximately disposed in the same plane and adapted to contact either with the article to be heated orwith an interposed plate of carbon or' equivalent material, which'in turn contacts with such article, as for example, the bond terminal in the case of the specific application of the process under consideration. A current commutating device, of which several forms are shown, is then utilized to supply the current in succession to the individual carbons of the electrode, the current being derived from the trolley or similai source and merely passing through a regulating resistance on its'wav to the device. sired, an inductive resistance may be utilized instead 'ofgthe simple regulating'resistance, and in place of a single such resistance, a plurality, corresponding with the number of separate elements in the electrode, may be employed.

By-the foregoing device, the current is caused to flow through the separate, ele ments of the electrode in succession, the return being through .the rail and usual ground return circuit. The connections-with the individualcarbons of the electrode are made and broken with sufiicient rapidity to avoid the formation of the harmful are be tween the same and the article being heated,

while the successive impulses of current will nevertheless be sufiicient to raise such carbons, or electrode elements, at their points of contactwith the article to a proper temperature to effect the desired welding operation.

The construction of the electrode may be very readily'explained by reference to Figs. 2. 3 and l. in which said electrode is illustrated as comprising six separate rods 1 held in a block 2 of vitrified fire clay, the

If de-- carbons preferably bloc]; to the rear and lying substantially flush r'it itor face, that is, the face uliich desi nod to be brought against the bond termina. A plate of carbon may be interposed bemveensuch inner ends of the carbon rot s or not, as desired. this arrangement being shown in the modified construe-- r m 7' .Y 1 a i i gs. i) lulu 0. Bvmeans of suitable clamps 3, electric conductors or leads 4 are attached to the respective outer ends of the carbon rods 1, the 1 purpose already explained. It has already been explained that an inductive resistance maybe substituted for such regulating re- 'sistance, if desired.

commutator brush '7 may be produced in The rotation of the any suitable fashion, a motor (not shown) .being conveniently provided for the purpose, operable by the trolley current. The rate of rotation will be varied to suit the character of'the current and the number of separate contacts or electrode elements.

The modified construction of electrode 10, illustrated in Figs. 5 and 6, is characterized by slightly differently shaped holder in which are mounted plurality of electrically separated carbon rods 1 as-before. The face of the holder designed to press the bond against the rail is provided with a recess 11 of approximately the same shape as the bond terminal, but a trifle shallower so that the latters inner face will project beyond the face of the holder a corresponding amount. Such bond-contacting face of the holder is furthermore provided With an overhanging portion 12 which is adapted to rest on the top of the rail and thus assist in locating the holder in proper relation to such rail. This overhanging portion is provided with an opening 18 that communicates with the recess 11, so that additional mateial may be supplied and melted in. such recess after the bond terminal has come to the melting poin if such additional material be necessary; or any excess of material formed by the fusion of the terminal, may esca e by tray of said opening 13, as through a spine opening. in this construction of electrode, moreover, the lower ends of the separate car ion rods do not rest directly on the inner ace of the holder, but a plate 14: of carbon, or other suitable high-resistance material, forms the back of the aforesaid recess 11 that is provided. Lil i holder face for the reception of the he... i material and projecting Without said.

' the heat, thus tion of the first is entir the endof the carbon rods bear against the rear face of this plate.- The forward face of the plate, of course, Will contact directly with the bond terminal and communicate thereto the heat generated by the successive application of momentary electrical impulses to the difierent rods. Such plate serves, in effect, as a distributor, merely, of generated. as will be readily understood.

Fig. 7, it has already been explained, illustrates a modification in the general arrangement of apparatus, such apparatus being Wholly diagrammatically shown in this figure. Instead of a sin le regulating resistance 8 interposed between the distributing commutator and the trolley Wire, or other source of current suipv', an inductive re sista'n'ce 15 is interposed in each of tie leads lfrom said commutator to L118 rate'carbon rods of the electrode. 1 has been explained that an inductive resistance, even if merely one be substituted for the single regulating resistance shown in Fig. 1, possesses certain advantages over the latter, in that'it prevents surges of current through the conductors -l, as the connection with the latter is-rapidly made and broken. This advantage is still further realized Where separate inductive resistances are interposed in each of the conductors or leads, shown in make and break the connection for half of the total number of ele trode elements, viz. for lhree in the construction illustrated, where there are six such elements, altogether. The corresponding rotating commutator members l8 and which effect such making and breaking of the circuits, are mountedso' as to rotate in unison but with the one 19 a trifle to the rear of the other 18, and so spaced that the connection for the second electrode element is madebefore the connecly broken, thus caus ing the impulses of current to said electrode element to overlap. two rotary members or contactors of the commutator Will be preferably carried on the armature shaft of the motor :20, W iich is illustrated in this figure, with proper connections 21 from the .1 in circuit for operating the same.

Other modes of ar plyi the principle of uy invention av be employed instead of the one eig ila ncd. change being made r cards the stros h in disclosed. pr vidcd the steps stated b any of the following claims or the eo'uivalent of such stated steps be employed.

has to fusibility, the more readily fusible and the contacting I therefore particularly point out and distinctly claim as my invention 1. The method of homogeneously uniting metal bodies having unlike characteristics body having also the greater heat conductivity, which consists in holding said bodies in contact at the desired point of union; anddirectly heating fusible body by pressing against the same an electrode composed of a plurality of electrically separated resistance, elements, and thereupon passing an electric current 'in rapid succession through said resistance elements and bodies, whereby said first body I face of the second body are brought to a welding temperature. 3. The method of homogeneously uniting metal bodies of unlike masses and different temperatures of fusion, the smaller body having both the lower temperature of fusion and greater heat conductivity, which consists in holding said bodies in contact at the desired point of union; and directly heat- .ing one of said bodies by pressing against the first or more readily.

the same an electrode composed of a plurality of electrically separated resistance elements, and thereupon passing an electric current in rapid succession through said resistance elements and bodies, whereby said first body and the contacting face of the second body are'brought to a Welding temperature.

- 4. T he method of homogeneously uniting a bond to a rail, which consists in holding the bond in contact with the rail at the desired point of union; directly heating said bond by pressing against the same an electrode composed of a plurality of electrically separated resistance elements, and thereupon passing an electric'current in rapid succession through said resistance elements, bond and rail, whereby said bond and the contacting face of the rail are brought to a Welding temperature. 5. The method of electrically heating a body, which consists in holding in Contact therewith a plurality of electrically separated resistance elements, and then passing an electric current through said resistance elements in rapid succession, such current being also passed through an inductive resistance, the period of current flow through any one element of said electrode being insufficient to produce any harmful arcing efiect.

Signed by me, this 26th day of November,

' ALBERT B. HERRICK, Attested byr Y D. T. DAYIE-S,

Jxo. F. OBERLIN. 

